Impellers are used in many different applications, one of the most demanding of which is in submersible pumps used for pumping sewage or other liquids having a solid content comprising rags or other material contaminants. These rags have a tendency to wrap themselves around the impeller, degrading the performance and ultimately clogging the pump. The pump must then be shut down and retrieved for repair, resulting in significant down time. The main clogging issue results from the rags becoming wrapped around or doubled over on the leading edge of the impeller vane, which both reduces the pumping performance of the vane, and leads to increased rag retention by the impeller.
There are also other clogging issues when using impellers for pumping liquids having rag or other solid content. For example the interior volume defined by the impeller vane may develop areas of low fluid circulation or even stagnation, within which pockets solids may gather, posing a further risk of clogging.
It is therefore an object of the present invention to provided a pump impeller which reduces or eliminates the above problems.